char *calculateGUID(char *key)
{
        char *hash;
        hash = do_MD5(key, 0x00b684a3);
        return do_MD5(hash, 0x00051a56);
}

/*
====================
CL_UpdateGUID

 * update cl_guid using ETKEY_FILE and optional prefix
====================
 */
static void CL_UpdateGUID(const char *prefix, int prefix_len)
{
        fileHandle_t    f;
        int             len;

        len = FS_SV_FOpenFileRead(ETKEY_FILE, &f);
//      FS_FCloseFile(f);

        if(len != ETKEY_SIZE)
                Cvar_Set("cl_guid", "");
        else
        {
                byte buffer[2048];
                int r = 0;
                int total = 0;
//              int length;

                for(;;)
                {
                        r = FS_Read2(buffer, sizeof(buffer), f);
                        if (r < 1)
                                break;
//                      if (r + total > length)
//                              r = length - total;
                        total += r;
//                      if (r < sizeof(buffer) || total >= length)
//                              break;
                }
                Cvar_Set("cl_guid", calculateGUID(buffer));
        }
        FS_FCloseFile(f);

//              Cvar_Set("cl_guid", Com_MD5File(ETKEY_FILE, ETKEY_SIZE, prefix, prefix_len));
}